The Doctor of Philosophy is the most common type of the highest level of university degree and is often applied to several fields of studies. There are three stages before an academic scholar achieves the title of Doctor of Philosophy or Ph.D.; they must have completed a bachelor's degree, a master's degree and, finally, they must have completed a dissertation to achieve the title of Doctor of Philosophy. This degree is often related to fields of studies under social sciences and humanities.
The Doctor of Juridical Science is the highest level of university degree that a person studying law achieves. This degree is also often called "Doctor of the Science Law." It is often abbreviated as S.J.D. or J.S.D. and it is more widely used in the United States and Canada. In order to get this degree, a person must first complete two degrees in law -- professional law and graduate level training. The J.S.D. often is pursued by law professors and other scholars in law.
In some countries such as the United Kingdom and Australia, the Doctor of Letters is the highest university degree that a scholar can earn in the field of humanities. This degree is recognized as a higher degree than Ph.D. and is often awarded to people who showed an exemplary performance in their field of study. The Doctor of Letters is also known as "Litteratum Doctor" and is often abbreviated as D.Litt. Achieving the Doctor of Letters degree requires the scholar to provide major published works together with a distinguished recognition and achievement in his field of study. Notable recipients of this degree include J.R.R. Tolkien, John Updike and Robert Frost. Some universities in the United States award this degree, as well, but these universities often award them as honorary degrees.
Just like the Doctor of Letters, the Doctor of Science is a university degree that is considered to be a higher doctorate degree than a Ph.D. This distinction is also commonly used in the United Kingdom and Australia. It is often awarded to individuals who were able to achieve an exemplary performance in the field of science. The awarding of the degree is similar to the process of getting a D.Litt. degree; the person must have exceptional published works and an international reputation of being a front-runner in his or her chosen field. In the United States, the Doctor of Science is considered to be on the same level of Ph.D.